Nikki Bella now doesn't want children until she's in her 40s.

The 34-year-old professional wrestler called off her engagement to John Cena earlier this year over their differing views about parenting, and now, despite John saying he would be happy to father Nikki's children, she has seemingly changed her mind on the matter.

Nikki revealed that her 15-month-old niece Birdie - whose mother is Nikki's twin sister and wrestling partner Brie Bella - has been ''the best form of birth control'', as she's now no longer sure whether she wants kids right now.

She said: ''[Birdie] has been the best form of birth control for me. Here I was dying to be a mom. Now I want to push it back. Can my clock tick until my 40s?''

Instead of children, the 'Total Bellas' star now believes ambition is what is keeping her and the 'Blockers' actor apart.

She added to The Post: ''One person had to sacrifice their career [for us to be together], but I'm not willing to do that. I'm just not the girl who hangs out on set. I have my own career. I want to be one of Forbes' top entrepreneurs.''

The former couple had previously pledged to try and work on their relationship following their split - which came just weeks before they were due to tie the knot - but admitted a month later that they were over for good.

Nikki said at the time: ''After I called off the engagement, we tried to work on our relationship to get back to where it was, and in order to move forward with our wedding. After much time and soul-searching alone and together, we have decided to officially part ways. I had a beautiful and loving 6-year relationship with a wonderful man. I have the utmost respect for John, but I know this is what's best for me.''